This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
During many medical procedures, various fluids are injected into patients for purposes of diagnosis or treatment. An example of one such fluid is contrast media used to enhance diagnostic images generated in imaging procedures such as, for example, angiography, MRI and CT procedures. Injectors used in these procedures tend to be automated devices that expel the fluid from a syringe, through a tube, and into the subject. Often, the syringes will be purchased by the user prefilled with fluid, such as contrast media, in varying volumes.
Syringes used in the above-described imaging procedures generally include a barrel with a hollow interior and a discharge tip, and a syringe plunger disposed within the barrel. The rearward face of the syringe plunger of many of these syringes is formed by a backer plate. The backer plate generally includes a first portion that supports a rubber cap to form the forward facing surface of the syringe plunger, and a second portion forming a rearward facing surface including a coupling element, which is engageable with a plunger drive ram of the injector.
In many syringe plungers, the coupling element includes an extension or extensions referred to as a “bayonet coupling.” A typical bayonet coupling may include two hook-like projections disposed opposite one another and protruding from the rearward facing surface of the backer plate. Each of the hook-like projections may include a stem portion, which projects from the rearward facing surface parallel to the longitudinal axis of the plunger, and a transverse arm portion, which extends from the proximal end of the stem portion in a direction perpendicular to the longitudinal axis of the plunger and toward the longitudinal axis of the plunger. When the syringe, including the syringe plunger and associated backer plate, is inserted into and coupled to an injector, the bayonet coupling contacts and couples to a plunger coupling element located on the forward end of the plunger drive ram. A typical plunger coupling element may include a “T”-shaped extension that projects from the forward end of the drive ram such that the stem of the “T” extends from the drive ram along the longitudinal axis of the drive ram, and the cap of the “T” is nearest to the rearward facing surface of the syringe plunger as the syringe is inserted into the injector. The syringe may be inserted in a manner such that the transverse arms of the hook-like projections do not confront or contact the cap of the “T,” but rather are inserted past the cap of the “T.” Once the transverse arms are positioned proximally of the top of the “T” of the T-shaped extension, the syringe may then be rotated relative to the plunger drive ram to bring the transverse arms of the hook-like projections into a confronting relationship with the T-shaped extension, thereby connecting the backer plate of the syringe plunger to the plunger drive ram, with the cap of the “T” positioned between the transverse arms and the rear face of the backer plate.
In another example of a syringe plunger, the coupling element may be an extension referred to as a “button,” which may include a shaft portion protruding from the rearward facing surface of the backer plate, topped by a cap portion. When the syringe, including the syringe plunger and associated backer plate is inserted into an injector, the button typically contacts a plunger coupling element, such as engagement jaws, located on the forward end of the plunger drive ram. These jaws may then snap around the button of the backer plate, thereby connecting the backer plate of the syringe plunger to the plunger drive ram.
One drawback of present injectors and syringes is in the differing coupling elements on various syringe plungers, and plunger coupling elements on plunger drive rams. Different syringes (e.g., those made by different companies) include different coupling elements on backer plates, and different injectors (e.g., those made by different companies) include different extensions on plunger drive rams, such that a particular syringe will not necessarily engage plunger drive rams of every type of injector. This may tend to result in a reduction of options that consumers have for syringes and injectors.